Telegraph repeater circuits



BEST AVNLABLE coP Patented Nov. 17, 1925. I

UNITEli STATES ELMER J. conovma'on imcnrun; enone'ra, assurance 'ro'nMEnIcaN TELEPHONE AND 'rnnnenarn coMrANY, a conronarron or may YORKI J'..".. f GL1 L-i 11- 1 1.

TELEGRAPH REPEATE I? CIRCUITS I Application filed November 1', 1923. Serial No. 672,169.

Toall whom it may concern:

Be it known that I, ELMER J. Coxovnn, residing at- Decatur, in the county ofDekalb and State of Georgia, 'hfiNB invented certain Improvements in Telegraph Repeater Circuits, of which the following-is a specification.

This invention relates to telegraph circuits, and more particularly to such circuits in which telegraph -repeaters are employed for the transmission of signals between two linesections.

- It is one of the featuresof the invention to provide telegraph circuits for-"repeater sets which apply battery to a line section of the* same pot'entialand polarity as the distant* marking battery, instead of opening the line to send the space signal. Vltll such circuits the leakage current through the relay at the opposite end of the line is reduced when the repeater is opened, thus affording more efficient transmission. Other and further features of the invention will appear more fully hereinafter.

The invention may be more fully understood-from the following detailed description, when considered in connection with the z'iccompanying drawing, in which Figure 1 illustrates a circuit diagram of one embodiment thereof, and Fig. 2 illustrates a modification of Fig. 1.

In the drawing L and L represent the line sections which are interconnected by the repeater set of this invention. The line sections terminate at stations WV and E, respectively,"and these stations are each provided with the usual apparatus including a relay and key. The repeater set consists of the ordinary line relays and holding coils, and the armatures for these are provided with back contacts which are connected to battery of the same potential and polarity as the distant marking battery.

In the drawing, the lines L and L are shown in their normal or closed position. The relays 5 and 6 of line L are energized by a circuit from positive battery 7, closed contact of key S, windings of said relays, make contact 27 of armature for relays 9 and 10, conductor 11 to negative battery 12. Relays 9 and 13 of line L are energized by a circuit through their windings from negative battery 1* and key 15, make contact 25 of armature for relays 6 and 16, conductor 17 to grounded positive battery 18. The holding coils 16 and '10 are deenergized under this condition-by a short circuitextending from battery 19, conductor-23, contact 22, conductor-24, ,contact 20, conductor 21 to-ground. r

rVvhen one station desires to signal-,an opposite station, 'for instance, when station W signals: stationE, thekeyB-Of station W is opened,- therebybreaking the circuit through relays 5 and 6, formerly described, thus .deerier'giZingtheserelays. Upon the release ofrelay,6,- its,armature falls :back, thus openingcontacts 2Q and 25 and closing back contact26. The openingfoficont'act 20 removes' the shunt. fronrholding coil '10, and

currentlnow; flows over a circuit from battery; l9,;'conductor 23,- maker contact 22, winding of; coil 10, conductor129 to ground,

thereby; energizing relay'lO. The opening of frontrcontact 25 andclosing of back contact 26 disconnects :positive battery 18 from the linesection L and connects negative battery '12 thereto over conductor 31 and back contact 26. The battery 12 isof the same polarity and, potential as battery 14 atstation E, and therefore'a' no-current conditionergists. online L at this time, and relays 9 and 13 release. The armature of relay 9, however, is not now released, due to the energization of holding coil 10 over the circuit previously outlined, which is of sufficient strength to hold said armature in an attracted position. The closure of key 8 at station W'- again restores the normal condition ofthe circuit as described above.-

The circuit operation just outlined, for sending signaling impulses from station to station E, is exactly the same in a reverse order when signaling impulses are sent from station E to station W.

The leakage efiect as considered in connection with line section L when station V is signaling station E, causes current to flow through relay 13 from negative battery 14 if the line is opened at the repeater, the amount of this current depending on the resistance of the leak. Relay 13 must be then adjusted to operate on a margin between the normal line current and the leakage current.

If, instead of opening line section L at the repeater, a battery of the same potential and polarity as negative battery 14 is connected to the line, the leakage current through relay 13 for a given leak will beleduced. 'sinceflthis is equivalent to connecting both ends of the line to the samenbatteryiv thereby reducing. the resistancehetween th battery and the leali Qahd'dwidiii'g ,the' c' rent through the two channels (thetwo ends of the line), and reducing the potentialdrop between the battery and the leak. Consequently, the current throught relay iwfis re duced, or the operating margin for this recerning-lealrage in connection with line section L P applies r as 1 well I toline section L when station E' is signaling station WVQ- 5 Q In 1 the relays 6 -and 9 are shown connected in series in their respective-lines for the'purpose of in'aintainingfa constant terminal impedance when a-line'is connected to v b'attery through either the front or' "back 'eontact of the opposite relay This is an imrespectively.

portant r'eature, especially when telegraph current is superposed on telephone W-ires. Fig-2' shows another arrangement of the repeater, in which the lines L 'and L "a re connected directly to the armatures'of relays '9 and 6, respectively. Relays"9"and6 are series with't-he b-atteriesconnected to""the tain specific form, it will be understood that it is notso limited, but may be embodied in many and widely varied arrangements without departing from the spirit of the invention as defined in the appended claims.

lVhat is claimed is: 4 'l-. A, telegrap h repeaten interconnecting twoil line sections, saidilrepeatei' Eincluding a relay. .for each line section, an armature for ayrb t y o cn ype a y onnecte 'lsta'iitfif ",n'fligflbfi of saidli'ne sebnbns"; tlie fianrfidntact oi" the armature et; the aelay associated with the other line section being connected to battery so po-led -toucausencnrrentwtontlow over said first line section in the same direction as the current flowing in the distant battery, and-a battery of -"op'posite polarity bonn'cted tothe back contact of said*a1'*mature so that when the armature rests upon said back-contact a nolin'e' sectio-iia 2. A telegraph repeater interconnecting two l ine sections, said repeaterincluding a normallyenergized: ire"l ay:':for I each: line :sec- :tion, an: armature for eaclr relay; said zarmature drawing a: front 1 contact; z connectedto battery of one polarity and aback-contact iconnected wfio 'ibattery mat -.-tl1e'? 1 opposite poriarityys and? terminals i lat- 2 each) line section '1 connected a"); battery ofi the zs amepolarity -aiid 'potentia-l' as the backacontact of the reny armature at the opposite "line section.

"telegraph repeater interconnecting two line sections,-"said repeater including a normally energized 'relay for each line section, an armature for each 'relay, said arma- 'tui'ef havinga: front contact connected to battery fiche polarityanda back'co ntact connected to battefyiof"tlie opposite polarity, terminalsezitaeacli line sect-ion connected to battery of the S'ame :polarity and potential as -the:backa contact-rot the relay armature at the opposite line section;andflmeanssin circuit witlve-ach-baclr contact for presenting constant terminal impedance when battery is reversed. l I

' In testimony whereof, I-have signed my name to this-specificationthis 30th day-of October, 1923. F

= ELMER J. CONOVER. 

